Wednesday, July 16, 2008

Baseball Bat Composition

Livescience looks at the physics of baseball bats and the apparently increasing number of broken bats (and injured fans and players) generated from the switch from ash to maple wood initiated by slugger Barry Bonds' use of maple. An increasing number of players have switched to maple, thought to be lighter, stronger and less prone to chipping than ash, allowing for greater bat speed and less turnover. Conversely, many of the traditional greats like Babe Ruth used hickory, which is heavier than either ash or maple.

"Hickory was a common wood, and it's still known today as a good strong wood," said Lloyd Smith, a mechanical and materials engineer from Washington State University. "But it is very heavy ... that was one of the criticisms, was that it was a heavy bat."

The desire for a lighter-weight bat (for faster swinging and higher batting averages) eventually led to the adoption of ash as the wood of choice for major leaguers. And it stayed the preferred type of wood up until a few years ago. But because it is lighter, ash is not as strong hickory.

"The problem with most wood is that strength is proportional to weight, so if you want a really strong wood, you can do that, but you end up getting an increase in weight," Smith explained. "And if you want a really light wood, you can do that, but you pay for it because your strength goes down. So there's this kind of optimum balance."

In the 1990s, maple started to make the rounds as an alternative. It was appealing because it was stronger (which is better for hitting longer distances) and less prone to flaking than ash, so players didn't go through bats as quickly. Most players still stuck to their ash bats, though — that is, until Barry Bonds got the single-season home run record in 2001, using a maple bat. Now, just a few years later, maple is no longer on the fringe.

"For 50 years, northern white ash was the wood. Today half of the bats in the major leagues are made out of maple. So it was a very dramatic shift," Smith told LiveScience."

The issue is that the modern woods used in bats break in dramatically different fashions, with ash prone to splitting or chipping in smaller chunks, and maple more prone to often catastrophically large jagged shards. Ash wood is ring porous, leading to the wood flaking, while maple is ring diffuse, with more evenly distributed pores in the wood grain, which makes the wood more durable but also more inclined to snap in large pieces when it does eventually break. The reduction in chipping may also lead a player to use a maple bat longer, since an ash bat would be replaced after chipping. The cracking in ash tends to follow the wood grain due its porous nature, while maple can break in almost any direction due to the more diffuse nature of its rings.

Another contributing factor is the reduction in the size of bat handles. More modern bats are produced with thinner handles to reduce weight, which also reduces the durability. The force of the impact of a baseball on a bat by a Major league player can exceed 5000 lbs.

I always wondered if there wasn't a better type of wood out there than either ash or maple after being informed of the switch during a game about a decade ago.

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